The majority of Americans went shopping between Thanksgiving and Cyber Monday, according to a survey by the National Retail Federation. (Massimo Percossi/European Pressphoto Agency-EPE/REX/Shutterstock)

Nearly three in four American adults went shopping — either online or in person — over Thanksgiving weekend,according to data released Tuesday by the National Retail Federation.

The 174 million Americans who shopped between Thanksgiving Day and Cyber Monday spent an average of $335 per person during that five-day period, the trade group said. The biggest spenders, millennials aged 24 to 35, paid out an average of $419.52 per person.

“The fundamentals of the economy remain strong,” Matthew Shay, the chief executive of the National Retail Federation (NRF), said in a media call Tuesday afternoon. “Things are setting up very well for a very strong finale to the year.”

Consumer confidence, meanwhile, continues to climb to 17-year highs. The consumer confidence index rose to 129.5 in November, up from 126.2 a month earlier, according to new data released Tuesday by the Conference Board.

In all, Americans are projected to spend about$680 billion this holiday season, marking a 3.6 percent to 4 percent increase from last year’s $655.8 billion, according to NRF estimates. Those figures are in line with last year’s 3.6 percent growth in holiday spending.

Among those who made purchases this holiday weekend, about 58 million people shopped online only, while 51 million shopped exclusively in stores. The remaining 65 million consumers shopped both online and in stores.

Last year, using different survey methods, NRF reported roughly 154 million Americans shopped during the four-day Thanksgiving weekend, up from 151 million the year before. Executives said those results could not be compared with this year’s estimates, which also include Cyber Monday.

Cyber Monday — the first day back at work for many Americans after Thanksgiving — has also become an important shopping day, particularly for those buying online. Americans spent a record $6.59 billion online on Monday, making it the largest Internet shopping day in history, according to data from Adobe Analytics. Nearly one-third of those purchases were made on a smartphone or tablet.

“We got off to a great start so we see positive momentum,” Shay said. “Having said that, this is just a half-time break: 91 percent of consumers still have shopping left to do.”

Correction: An earlier version of this story stated that 70 percent of Americans shopped during Thanksgiving. It is 70 percent of American adults, according to the National Retail Federation. This version has been updated.